Preheat the oven to 425 degrees F. Line a baking sheet with parchment.
Whisk together the flour, sugar, baking powder, garlic powder and salt in a medium bowl.
Stir in 1 1/2 cups of cream and the herbs and mix with a wooden spoon until the dough comes together. Remove the dough to the countertop and knead briefly until it is smooth and uniform in appearance. Pat the dough out to a 1-inch thickness. Use a 2 1/2-inch biscuit cutter dipped in flour to punch out dough rounds. Push the leftover dough together cut out more rounds. Arrange the biscuits on the parchment lined sheet tray.
In a small bowl, whisk together the remaining 1 tablespoon of cream and the egg. Brush the tops of the biscuits with the egg wash and sprinkle with kosher salt. Put immediately into the oven and bake for 18 minutes. Transfer the biscuits from the oven to a serving platter and serve.